Attachment-plug.



H.P.ROUNDS.

ATTACHMENT PLUG.

APPLTCATTON HLED OCT EH. T913.

1,160,531 Patented Nov. 16, 1915.

INVENTOR HIS ATTORNEY IN FACT earner orricn HARRY P. ROUNDS, 0F DETROIT, MICHIGAN.

ATTAcHMEN'r-PLUG.

Specification of Letters Patent.

Patented Nov. 16, 1915..

Application filed October 31,1913. Serial No. 798,481.

' out the necessity'of twisting tliei la mp cord attached thereto.

This, and other obyects, which will be made apparent throughout the further deof this application.

scription of the invention, 1 attain by means of an attachment or plug embodying the features herein described and illustrated in the drawings accompanying and forming a part In the drawings: Figure 1 is a perspective view of a contact carrying element which forms a detail of my invention; Fig. 2 is a perspective view of a collar or eccentric which forms a detaihof the present embodiment of my invention; Fig. 3 is a per spective view of the body portion of the plug illustrated; Fig. 4: is a perspective view, of

' the element shown in Fig. 1', but with the shank turned so as to disclose the electrical contacts or terminals of the plug; Fig. 5 is a side elevation of the plug as it appears with the parts in position for being inserted into a socket and Fig. 6 is a side elevation of the plug as it appears with the parts in the relative positions they occupy when the plug is locked in place in a socket. V

The plug illustrated as an embodiment of my invention includes three essential elemerits; a body 7, a contact or terminal carry tit) - which, as shown, is

mg element 8, andan eccentric or collar 9, which is rotatably mounted .on the shank of the element 8 and is located between the contact carrying end thereof and the body 7.

The body 7 may be formed of any suitable insulating material, such, for I example, as hard rubber, and as illustrated, is provided with acentral longitudinally extending opening 11, into which the shank of the element 8 's adapted to proJect, and 1n which it is adapted to be secured byany suitable means, such, for example, as a set screw 12, adapted to be screwed into a radiallyextending apertureformed in the body and to abut against the shank, and

thereby lock it rigidly to the,body. The shank of the element 8 is preferably made entirely of insulating material, such as hard rubber, and, as illustrated, consists of a cylindrical or shank portion and a head portion 12. The shank, as illustrated, is provided with a groove 13 andan aperture 14 for the reception of the separate wires of the lamp cord attached to the plug, but it will, of course, be understood that the shank may be provided with two grooves or twoaper- I tures as desired. The head 12 is substantially cylindrical and is preferably formed integrally with the shanlqbut is located eccentrically thereof, and, if desired, is provided on its periphery with convolutions or threads, which may conform in contour to the con-volutions or threads formed in the cylindrical or screw contact 15,which is mounted on the head and extends circumferentially around it, The end ontact, or end terminal, 16 is shown secured to the head 12 by means of a contact screw 17, and is lo cated centrally with relation to the head, and

is spaced from the screw terminal 15 so that y it is insulated therefrom. One of the cords, or wires, 18 is shown extending along the groove 13 and electrically connected to a tongue or extension 19 provided on the screw terminal 15, while the other wire 18 is shownas extending through the aperture, 14 and is electrically connected to the end terminal 16 by any suitable means. If desired, the wires 18' may extend around the screw 17, between the terminal 16 and the head portion, and may be forced into contact with the terminal 16 by means of the screw 17 The collar 9, as illustrated, is substantially cylindrical, although it is desirable totaper it slightly, as shown in the drawings, from the body 7 toward the head 12. The collar is provided with an. eccentrically located, but axially extending opening 21, through which the shank proper of the member 8 is adapted to extend. An arc shape flange 22 extends partially around the outer edge of the collar and projects axially with relation vatur'e of the flange 22 is locatedcentrally which extends radially. The center of cur of the collar, but eccentrically of the opening 21, and the flange projects from that portion of the edge of the collar which is located farthest from the opening 21.

In the apparatus illustrated I have shown the .body 7 provided with springs 24 for normally forcing the collar 9 along the shank,

away from the body, and against the shoulder formed by the construction of the head 12 on the shank. As illustrated, the springs are stamped or cut from the ring 25, which is secured in place within an annular groove formed in the end of the body. These springs not only yieldingly press the collar outwardly away from the body, but they also create sufficient. friction between the head and the collar to hold the collar in the positions 'to which it may be turned so that it will not shift its position by reason of its own weight. 7

In assembling the separate parts of the plug, the wires 18 and 18"are attached to their respective terminals in the usual manner, or aspreviously described. The collar 9 is then rotatably mounted on the shank proper of the member 8 and the body 7 is moved to position over the shank with the wires extending through the end of the opening formed in the body as shown in Figs. Sand 6. The set screw 12 is then driven home so that it rigidly locks the shank and the body together.

In preparing the plug for insertion into a socket, the collar 9 is turned about the shank so that it occupies a position substantially concentric with the head 12, in which the 'flange 22 contacts with the screw terminal 15. It will be understood that the eccentricity of the head with relation to the shank proper of the member 8 is substantially equal to the eccentricity of the collar with relation to the opening 21 of the collar and that the curvature of'the flange 22 is substantially equal to the curvature of the peripheral face of the screw contact 15. It will also be understood that the flange 22 is of such length cir'curnferentially of the collar that it forms a stop for the collar by its engagement with the head whenthe collar is moved to an eccentric position with relation to the'head. 4

In securing the plug in place in the socket, it'is inserted into the opening of the socket and pressed inwardly relatively to the socket, so that its contact 16 engages the inner or central contact of the socket and so that the tapered peripheral face of the collar 9 is engaged by the cylindrical or threaded terminal of thesocket. It will beunderstood by reference to the drawings that the body is preferably so located on the shank portion of the member 8 that the springs 24:

normally maintain a clearance between it i and the collar so that the collar can be This completes the assembling operation of the plug.

moved awayfrom the head 12 by its engagement with the socket when the plug is forced into place. With such an arrangement the frictional, grip between the collar 9 and the head 12 will lee-broken, and the? friction between the collar and the engagingterminal of the socket will be greater than that between the collar and the shank.

-lVhile the plug is thus pressed into theby the socket and since the shank is rigidly secured to the body. The grooved or threaded surface of the cylindrical terminal 15 of the head is therefore forced into engagement with the threads of the cylindrical terminal of the socket, and consequently'completes' the electrical circuit, and also locks the plug in place within the socket. The clearance between the collar and the body 7 also comes into during the operation of turning the terminal 15 into engagement with the cylindrical terminal of the socket, since it permits the head 12 to move longitudinally of the collar an amount sufficient to insure an effective engagement between the threads of the terminal 15 and the threads of the socket terminal. In releasing the plug, it is turned to the left; that is. in an opposite direction from that which it is turned in securing it to the socket. This moves the head to the position shownin Fig. 5. or, in other words, to a position substantially concentric withthc collar 9 and therefore releases it from the engagement of the threads of the cylindrical terminal of the socket, so that it may be easily withdrawn from the socket.

In accordance with the l nited States patent statutes, I have illustrated what I now consider the preferred embodiment of my invention, but I desire it to beunderstood that various changes, modifications, substitutions, additions, and omissions may be made in the apparatus illustrated without departing from the spirit and scope of my invention as set forth by the appended 2.'A plug comprising a. body, a shank mounted on the body and having an eccentrically located terminal-carrying head, and a collar rotatively mounted on and movable ecc'entrically around the shank and located eccentrically with relation to the shank.

A plug of the character described, comprising a body, a shank rigidly mounted on the body, a terminal-carrying head carried by the shank and locatedeccentrically with relation thereto, and a collar, having an eccentrically located shank engaging opening,

rotatively mounted on the shank, between the body and the head, and movable around the shank from a concentric to an eccentrlc position with relation to the head. I 4. A socket-engaging plug of the characterdescribed, comprisinga body, a shank rigidly mounted on the body and having an located terminal carrying, socket-engaging head, and socket-engaging means, having a tapered peripheral surface and an eccentrically located shank engaging opening formed therein, rotatively mounted on the shank and moyable around the shank to force the head into locking engagement With a'socket into which the head and the iiieans are inserted. I

51A plug comprising a body, a shank rigidly mounted on the body and having a terminal carrying head eccentrically mounted thereon, a collar rotatably mounted ecc'entrically on the shank between the head and the body, and having an axially projecting flange partially encircling the head, an an annular radially projecting socket engaging flange formed adjacent to the body, and means for yieldingly'forcing the eccentric along the shank toward the head.

6. A terminal plug. comprising a body, a shank mounted on the body, a terminal car: rying member mounted on the shank and located eccentrically with relation thereto, and a socket-engaging collar having an eccentrically located shank-engaging opening cally having an eccentrically located shank engaging opening therein, rotatively mounted on the shank between the member and the body, and movable around the shank to eccentric and concentric positions with relation to said member, said collar being tapered from the body toward the member.

8,. A terminal plug comprising a body, a

shank mounted on the body, a terminal car rying member located eccentrically on the shank, a collar having an eccentrically located shank-engaging opening rotative'ly mounted on the shank and having a tapered socket engaging perlpheral surface.

9. A terminal plug comprising a b0dy,*a'

shank on the body, a terminal-carrying head located eccentricall'y' on the shank, and a socket-engaging collar having an eccentrilocated shank-engaging opening formed therein, rotatively mounted on the shank between the body and the head and movable about the shank to eccentric and concentric positions with relation to the head, and provided with an'axially projecting flange partially encircling the head.

In testimony whereof, I have hereunto subscribed my name this 28th day of October, 1913.

HARRY P. ROUNDS. Witnesses:

MARIE GREEK,

CHAS. B. WHITING. 

